Volume effect in magnetic properties of the YCo4Si compound

Abstract Si substitution in YCo 5 compound results in a dramatic reduction of both the Curie temperature and Co magnetic moments. The magnetic properties of the YCo 4 Si compound have been investigated at ambient and high pressures. YCo 4 Si is ferromagnetic with a Curie temperature of 320 K only and a significantly reduced magnetization in comparison with YCo 5 . The logarithmic pressure derivative of saturation magnetization M S can be estimated dln M S /d p =(−3.0±0.5)×10 −3 kbar −1 . The effect of pressure on the Curie temperature has been investigated up to 12 kbar. The Curie temperature, determined from thermomagnetic measurements in a low field (0.01 T), is also found to be sensitive to the applied pressure dln T c /d p =(−1.25±0.5)×10 −3 kbar −1 . It is found that the large reduction of the magnetic properties is due to both a chemical and a pressure effect of the Si for Co substitution.